This kind of thickness measuring device is disclosed in, for example, Patent Document 1. The ultrasonic diagnosing device of Patent Document 1 is configured to perform a property diagnosis of blood vessel wall tissues. The ultrasonic diagnosing device is provided with an ultrasonic probe supported to closely contact with the body surface of an examinee. The ultrasonic probe includes a plurality of ultrasonic oscillators arranged in an array state. The ultrasonic diagnosing device transmits ultrasonic waves from the ultrasonic probe to the inside of body tissues of the examinee including the extravascular tissue and blood vessels. Then, some of ultrasonic waves reflected on the blood vessels, etc. and scattered, return to the ultrasonic probe and received as echoes. Here, by controlling a delay time length of a drive pulse signal supplied to the ultrasonic oscillator group, a direction and a focus depth of an acoustic ray of each ultrasonic beam transmitted from the ultrasonic probe are changed. Further, by controlling a delay time length of each of the reception signals of the respective ultrasonic oscillators, an opening diameter and a focus position of the ultrasonic probe can also be changed.
The ultrasonic diagnosing device of Patent Document 1 performs analysis and calculation of the reception echo signals and obtains elasticity of the extravascular tissue and the blood vessels. Note that, the ultrasonic diagnosing device of Patent Document 1 has a configuration basically of obtaining a change amount of a thickness between two positions, but it is also disclosed that the thickness between the two positions itself can also be obtained in a case where particular information, such as initial values of the two positions, is provided.
Patent Document 1 discloses the ultrasonic diagnosing device configured to mainly measure the blood vessel wall tissues, and as osteoporosis recently comes to draw much attention, it has been considered to measure a thickness of the cortical bone which is said to have a strong relationship with bone mass. For example, Non-patent Documents 1 and 2 disclose arts for deriving the thickness of the cortical bone by performing spectral processing on echoes from the outer and inner surfaces of the cortical bone. Further, in Non-patent Documents 3 and 4, methods of calculating to obtain the thickness of the cortical bone by using low-frequency lamb waves are proposed.